req2.Header.Set("User-Agent", u.ua)
	return u.rt.RoundTrip(req2)
}

// WithUserAgent wraps an existing transport with custom User-Agent
func WithUserAgent(rt http.RoundTripper, getUA func() string) http.RoundTripper {
	return &uaTransport{
		ua: getUA(),
		rt: rt,
	}